Originally Posted by
HNLbasedFlyer
I'm a bit surprised the FAA would grant a waiver to fly a grounded plane permission to fly
Ferry permits are common and routine. They include restrictions, requirements, and procedures to mitigate the risk of whatever it is that is otherwise causing the airplane to be grounded.
I don't know any specifics about these ferry permits but I'm sure there are maintenance procedures and requirements to mitigate the risk of fan blade failure. Perhaps they have to install relatively low-time blades? Maybe there's some time of inspection that they must do? I don't know.